Known examples of the high-performance rare earth magnet include an Sm—Co-based magnet, an Nd—Fe—B-based magnet, and a similar magnet. Fe and Co in such magnets contribute to an increase in saturation magnetization. These magnets contain a rare earth element such as Nd and Sm. Derived of a behavior of 4f electron in the rare earth elements at a crystal field, the rare earth elements bring about large magnetic anisotropy. This creates a large coercive force, thereby providing a high-performance magnet.
Such high performance magnet is mainly used for electrical devices such as a motor, a speaker, and a measuring instrument. In recent years, requests on downsizing, weight reduction, and low power consumption have been increased on various electrical devices. In response to the requests, there is a demand for a permanent magnet with higher performance that has an improved maximum magnetic energy product (BHmax) of the permanent magnet. Also in recent years, the variable magnetic flux motor is proposed and this contributes to an improvement in efficiency of a motor.
Since the Sm—Co-based magnet features high Curie temperature, the Sm—Co-based magnet can achieve good motor property at high temperature. However, a higher coercive force, higher magnetization, and an improvement in a squareness ratio have been desired. It is presumed that high concentration of Fe is effective to increase the magnetization of the Sm—Co-based magnet. However, with the conventional manufacturing method, high concentration of Fe tends to deteriorate the squareness ratio. In order to provide a high-performance magnet for motor, therefore, a technique that achieves the good squareness ratio while improving the magnetization with the high Fe concentration composition is necessary.